Bright but disadvantaged teenagers are almost half as likely as their richer classmates to study – and get good grades – in the A-level subjects that will help them to gain places at the UK's top universities, a study shows.
They are also much less likely to get three A-levels in any subjects.
The research published today also suggests that going to a decent nursery, reading for pleasure, attending an outstanding school, taking part in school trips and doing homework every day can boost a disadvantaged pupil's chances of getting good results.
The study by the Oxford University Department of Education is based on data about more than 3,000 young people who have been tracked from the age of 3.
The researchers looked at data for a group of disadvantaged children who had obtained level 5, the standard expected at age 14, when they were just 11.
They found that only a third of bright but disadvantaged students went on to take one or more A-levels in so-called "facilitating" subjects, compared with 58 per cent of their wealthier peers with the same academic ability.
Facilitating subjects are those required most often by Russell Group universities, which are considered to be among the best institutions in the UK. The subjects include English literature, maths, physics, biology, chemistry, geography, history and languages.
Less than a fifth (18 per cent) of the poor students tracked in the study gained at least a B in these subjects, compared with 41 per cent of their more affluent classmates.
The findings also show that just over a third of the disadvantaged sixth-formers gained three A-levels in any subjects, compared with 60 per cent of their peers.
An analysis of the data shows that sixth-formers who did two to three hours of homework each night were nine times more likely to gain three A-levels than those who did none.
"Spending time on homework is likely to reflect both student motivation and engagement, study skills and independence, school policies and the priority teachers attach to encouraging students to study at home (or provide opportunities after school), as well as parental attitudes and support," the report says.
The study concludes that reading for pleasure, educational trips, going to a good nursery and school, feedback on schoolwork and a supportive home life can help disadvantaged young people to get good results.
It suggests that bright, poor students should receive "enrichment" vouchers, funded through the pupil premium, to help with educational trips, reading for pleasure and studies outside the classroom.
Sir Peter Lampl, chairman of the Sutton Trust, which commissioned the report, said: "The fact that bright, disadvantaged students fall so far behind when they reach their A-levels shows that government and schools urgently need to do more to support able students from less advantaged homes.
"We must ensure that access to the best schools and opportunities for academic enrichment outside school are available to all students. It is also vital that schools advise their students on the right subject choices at GCSE and A-level so as to maximise their potential."
Professor Pam Sammons, co-author of the report, said: "There is no silver bullet that alone can make a difference but a combination of good schools and preschools, the right home learning environment and supportive teachers ready to monitor progress and provide good feedback can all ensure that bright but disadvantaged students get the chance of a good university education. There are important lessons here for teachers and policymakers seeking to reduce the equity gap in attainment."